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The simple answer to this is, that some of the objects that you're trying to pass has not been initialized (or putting it simple, does not exist; is null). Try to create an instance of all of the objects, and their properties that are requried to be passed on as a parameter.
Are all of your objects initialized?
The sh*t I complain about
It's like there ain't a cloud in the sky and it's raining out - Eminem
~! Firewall !~
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Your Code is behaving the correct way. box1,box2,box3 cannot be moved becaused you did not handle the events to move them but stackPanels which are the Children can move.
Vuyiswa Maseko,
Spoted in Daniweb-- Sorry to rant. I hate websites. They are just wierd. They don't behave like normal code.
C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.com
vuyiswa[at]dotnetfunda.com
http://www.Dotnetfunda.com
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In my application I have a window with a custom look and title bar. The XAML for my window is:
<Window x:Class="TicketWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Ticket Window" Height="300" Width="300"
WindowStyle="None" ShowInTaskbar="False">
<WindowChrome.WindowChrome>
<WindowChrome CaptionHeight="{Binding ActualHeight,ElementName=titlebar}"/>
</WindowChrome.WindowChrome>
<DockPanel LastChildFill="True">
<Border Background="{DynamicResource {x:Static SystemColors.ScrollBarBrushKey}}" DockPanel.Dock="Top" Height="25" x:Name="titlebar">
<TextBlock Text="{Binding Title, RelativeSource={RelativeSource FindAncestor,AncestorType=Window},FallbackValue=Title}"
Margin="10,0,0,0"
VerticalAlignment="Center">
<TextBlock.Effect>
<DropShadowEffect Color="White" ShadowDepth="3"/>
</TextBlock.Effect>
</TextBlock>
</Border>
<Border BorderBrush="LightGray" BorderThickness="1" Padding="4">
<TextBlock><Run Text="Window content"/><InlineUIContainer>
<Button Content="Button" Width="75" Click="Button_Click"/>
</InlineUIContainer></TextBlock>
</Border>
</DockPanel>
</Window>
I would like to be able to blink the title bar under some circumstances from a second thread using a loop. For testing purposes I am using the button to start the thread to blink the title bar between green and red with a half-second delay in between the changes.
In the button's click event I create a thread and start it:
Private Sub Button_Click(sender As Object, e As RoutedEventArgs)
Try
Dim thread As New Thread(AddressOf ChangeTitleBarColor)
thread.Start()
Catch ex As Exception
Dim m As String = ex.Message
End Try
End Sub
I've only used the Dispatcher a couple of times, so to initially test the ChagneTitleBarColor method and ensure I was using the Dispatch correct I used the following code:
Private Sub ChangeTitleBarColor()
Try
titlebar.Dispatcher.Invoke(Threading.DispatcherPriority.Render, Sub()
titlebar.Background = Brushes.Green
End Sub)
Thread.Sleep(500)
titlebar.Dispatcher.Invoke(Threading.DispatcherPriority.Render, Sub()
titlebar.Background = Brushes.Red
End Sub)
Thread.Sleep(500)
Catch ex As Exception
Dim m As String = ex.Message
End Try
End Sub
And this worked; the title bar went from the default grey to green, there is a half-second delay, and then the title bar changes to red. Next I tried the following code:
Private Sub ChangeTitleBarColor()
Try
titlebar.Dispatcher.Invoke(Threading.DispatcherPriority.Render, Sub()
titlebar.Background = Brushes.Green
Thread.Sleep(500)
titlebar.Background = Brushes.Red
End Sub)
Catch ex As Exception
Dim m As String = ex.Message
End Try
End Sub
However the title bar never turns green with the above code; it goes from grey to red. So I took the the first version of the ChangeTitleBarColor and added a loop so the title bar would switch between green and red indefinitely:
Private Sub ChangeTitleBarColor()
Try
While True
titlebar.Dispatcher.Invoke(Threading.DispatcherPriority.Render, Sub()
titlebar.Background = Brushes.Green
End Sub)
Thread.Sleep(500)
titlebar.Dispatcher.Invoke(Threading.DispatcherPriority.Render, Sub()
titlebar.Background = Brushes.Red
End Sub)
Thread.Sleep(500)
End While
Catch ex As Exception
Dim m As String = ex.Message
End Try
And this works fine as well.
I even tried adding another Thread.Sleep(500) after the changing the color to red and a call to an empty action (Private EmptyDelegate As New Action(Sub()End Sub) ) using the Dispatch.Invoke before each call to the sleep method of Thread and it still didn't work.
I would appreciate it if someone could explain why if I change the title bar twice in the single invoke statement (as in the second example of the ChangeTitleBarColor below) why the color only changes a single time? Is there a simpler way to switch the title bar between two colors indefinitely from a second thread?
Thank you in advance. Any help would be greatly appreciated.
A black hole is where God tried to divide by zero.
There are 10 kinds of people in the world; those who understand binary and those who don't.
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Hi,
I am setting the selected index of combobox in ViewModel constructor. After setting the selectedIndex I have fire the SelectionChanged event. Kindly help me.
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With Google now having screwed Silverlight by removing support NPAPI what future does it have, if any?
Should we start looking at HTML5? Or is there something better coming?
TIA
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That is really a question for Microsoft to answer.
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Microsoft recommends using HTML5 for web based applications. Silverlight is purely in maintenance mode now.
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Never used them or stumble on any custom implementation of them.
Dunno why I need them! Nor how I should write them!
Any tips or explanation please?
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Automation Peers allow us to programatically control UI elements from outside the application (i.e., to do things like automated UI testing).
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[UPDATE]
Figured it out. Was binding to the event instead of the Handler
[UPDATE]
I created a user control with this event:
public partial class AssignedEmployeesControl : _BaseUserControl
{
public static readonly RoutedEvent AssignmentRemovedEvent =
EventManager.RegisterRoutedEvent("AssignmentRemoved",
RoutingStrategy.Bubble, typeof(RoutedEventHandler),
typeof(AssignedEmployeesControl));
public event RoutedEventHandler AssignmentRemoved
{
add { AddHandler(AssignmentRemovedEvent, value); }
remove { RemoveHandler(AssignmentRemovedEvent, value); }
}
protected void OnAssignmentRemoved()
{
RaiseEvent(new RoutedEventArgs(AssignmentRemovedEvent));
}
I then add my control to a DataGrid in another control
<DataGridTemplateColumn Header="Assigned Employees"
Width="*">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<vc:AssignedEmployeesControl EngineRef="{Binding
ElementName=employeeJobAssignmentsView, Path=EngineRef}"
AssignmentShift="{Binding Shift}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="AssignmentRemovedEvent">
<i:InvokeCommandAction
Command="{Binding ElementName=employeeJobAssignmentsView,
Path=AssignmentRemovedCommand}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</vc:AssignedEmployeesControl>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
I then have a command to catch the event:
private ICommand _AssignmentRemovedCommand;
public ICommand AssignmentRemovedCommand
{
get
{
if (_AssignmentRemovedCommand == null)
_AssignmentRemovedCommand = new RelayCommand(p =>
assignmentRemovedExecuted(), p => assignmentRemovedCanExecute());
return _AssignmentRemovedCommand;
}
}
private bool assignmentRemovedCanExecute()
{
return true;
}
private void assignmentRemovedExecuted()
{
}
When I run it, my control calls OnAssignmentRemoved, but the host control's assignmentRemovedExecuted method never fires.
I get no compilation errors or ouput methods. I get no response at all.
Can anyone see what's wrong?
Thanks
If it's not broken, fix it until it is
modified 18-Dec-14 16:01pm.
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First the main issue:
I have a Path that I create at runtime and show it on a custom control. This part works perfect. The visual tree is simple:
Control
-Line
-Control
--Grid
---Path
UseLayoutRound=True, SnapToDevicePixels=True. Line is a 1 pixel tall horizontal line and the user can customize the vertical position.
I need to stroke the path in two different colors. One color for above the line and one color for below the line. Typical solution I see is to use a 2 color brush. However, as you might suspect, it is *EXTREMELY CRITICAL* visually that the color change happen *EXACTLY* on the horizontal line. +/- 1 pixel is not acceptable.
The problem I'm having seems to be to align the color change on the line 100% of the time. For example, if my control is 99 pixels high and the threshold is at 50%, I should have 49 + 1 + 49.
I have tried the following solutions… problems I encountered are listed as well. Any way to get this working perfectly 100% of the time?
1) Vertical LinearGradientBrush
Generally works and hits the line 100% of the time, but it doesn’t give me a hard break between the two colors, so for example black going into white will leave a gray line
2a) DrawingBrush with RectangleGeometries
2b) DrawingBrush with DrawingContext
Both of these ideas have the same problem. I can’t hit the line 100% of the time (round off errors I’m guessing…) but I’m using the same math as with #1, so…
I can get a hard color change with both these, but I get +/- 1 pixel off errors…
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My first thought would be to draw the line twice.
Once as a TWO pixel tall line in one color,
then again as a ONE pixel tall line in the other color, overwriting half of the line.
I don't know how accurately this would work...
A positive attitude may not solve every problem, but it will annoy enough people to be worth the effort.
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The problem seems to be that DrawingBrush has round-off errors internally or it doesn't work the same way as the LinearGradientBrush in terms of origin / relative ratios. Like I said, LinearGradientBrush hits the line consistently with my "math". DrawingBrush isn't even consistent at 50% which should not even be suspectible to round-off errors since its a whole pixel. Sometimes its 1 pixel too high, sometimes its 1 pixel too low. Also tried TransformToVisual to go from the line to the path, but TransformToVisual considers both shapes to be the same height (as the height of the control), so it just maps the points 1 to 1. Tried Math.Round() and Math.Ceiling(), etc. LOL. The line itself certainly doesn't move around, its always at the exact correct location. Tried get the rendered bounds of the path and calculating it from that, but same thing... +/- 1 issues. Also tried setting everything to absolute mode and setting the rectangles identically, nope... Maybe the LinearGradientBrush only *appears* to be working and is hiding the +/- 1 issues with the gradiented color switch.
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I have a DataGrid with a Date column. I need to show the date as:
"Wed, 12 Dec" - Short day, day number, and short month
I've tried a bunch of options, including these[^], but I can't get it to work.
What's the correct XAML for this?
Thanks
If it's not broken, fix it until it is
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Technically accurate but practically useless.
I didn't ask for the ISO standards.
What's the XAML?? I tried a bunch and it won't compile.
If it's not broken, fix it until it is
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Kevin Marois wrote: I tried a bunch and it won't compile. Interesting, but you cannot expect people to guess what that bunch comprises.
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Which is exactly why I provided the link to what I tried
If it's not broken, fix it until it is
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PIEBALDconsult is completely right. You need to change MM/dd/yyyy to custom format. Try!
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I HAVE been trying. I can't get it... Which is why I ask what the syntax was.
If it's not broken, fix it until it is
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I knocked together a quick sample to test. As long as you're binding to a DateTime field, you can use syntax like this:
<DataGridTextColumn Binding="{Binding CurrentTime, StringFormat='{}{0:ddd, dd MMM}'}" Header="CurrentTime"/>
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Thank you Pete. That did it!
I think I was missing the leading braces.
If it's not broken, fix it until it is
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You're welcome. Yeah, that would cause issues.
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